Projection device

ABSTRACT

A projection device includes: a housing that includes a base portion and a protruding portion protruding from the base portion; a projection lens that projects image light onto a projection target, is disposed to face the protruding portion, and is mounted on the base portion; a prism that is disposed in the base portion to face an incident-side end part of the projection lens; a plurality of transmission type electro-optical elements that are arranged to face a plurality of side surfaces of the prism, respectively; and a semiconductor light source that is disposed in the protruding portion and generates the image light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of InternationalApplication No. PCT/JP2020/023078, filed Jun. 11, 2020, the disclosureof which is incorporated herein by reference in its entirety. Further,this application claims priority from Japanese Patent Application No.2019-121324, filed Jun. 28, 2019, the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The technique of the present disclosure relates to a projection device.

2. Description of the Related Art

A projector as a projection device for projecting an image onto a screenhas been widely distributed. A projector comprises, for example, animage forming panel as an electro-optical element, such as a liquidcrystal display (LCD) or a digital micromirror device (DMD: registeredtrademark), a light source that emits light used to generate imagelight, and a projection lens that projects the image light formed by theimage forming panel onto a screen.

Projectors comprising projection lenses, which can change the projectiondirection of an image, have been developed as such a projector (seeWO2018/055964A, WO2019/107413A, and the like). In these projectors, animage forming panel, a light source, and the like are housed in ahousing that is a body part and a projection lens is mounted on theouter peripheral surface of the housing.

In the projectors disclosed in WO2018/055964A and WO2019/107413A,luminous flux representing an image formed by the image forming panel isincident on the projection lens from the body part. The projection lenscomprises a bending optical system having three optical axes, that is, afirst optical axis, a second optical axis, and a third optical axis inthis order from an incident side. The first optical axis is an opticalaxis corresponding to luminous flux incident from the body part, and thesecond optical axis is bent at an angle of 90° from the first opticalaxis. The third optical axis is an emission optical axis which is bentat an angle of 90° from the second optical axis and along which luminousflux is emitted to a screen.

Further, in the projector disclosed in WO2019/107413A, a part of thehousing is provided with a storage portion for storing the projectionlens and the projection lens is mounted on the housing to berotationally movable between a first position at which the projectionlens is stored in the storage portion and a second position at which theprojection lens protrudes from the housing.

On the other hand, JP2014-112258A proposes a projector comprising aliquid cooling device that cools heat sources, such as theelectro-optical element and the light source, with cooling liquid, athermoelectric conversion element that lowers the temperature of thecooling liquid of the liquid cooling device, and an air cooling devicethat supplies cooling air to the heat sources.

SUMMARY OF THE INVENTION

An object of a technique of the disclosure is to provide a projectiondevice which includes a housing including a protruding portion and aprojection lens disposed to face the protruding portion and in which thetemperature rise of each of a light source, an electro-optical element,and a prism is likely to be suppressed and an optical path length to theelectro-optical element from the light source is likely to be increased.

A projection device according to an aspect of the disclosure comprises:a housing that includes a base portion and a protruding portionprotruding from the base portion; a projection lens that projects imagelight onto a projection target, is disposed to face the protrudingportion, and is mounted on the base portion; a prism that is disposed inthe base portion to face an incident-side end part of the projectionlens; a plurality of transmission type electro-optical elements that arearranged to face a plurality of side surfaces of the prism,respectively; and a semiconductor light source that is disposed in theprotruding portion and generates the image light.

It is preferable that the semiconductor light source is a semiconductorlaser.

It is preferable that the projection device further comprises awavelength conversion element provided in the base portion andconverting a wavelength of laser light emitted from the semiconductorlight source.

It is preferable that the wavelength conversion element is disposed tobe close to a side surface, which is closer to the protruding portion,of two side surfaces of the base portion facing each other.

It is preferable that a control board is disposed in the base portionand the control board is disposed to be close to a side surface, whichis farther from the protruding portion, of two side surfaces of the baseportion facing each other.

It is preferable that each of the plurality of transmission typeelectro-optical elements is a liquid crystal display device.

It is preferable that two electro-optical elements among the pluralityof electro-optical elements are arranged to face each other with theprism interposed therebetween.

It is preferable that the projection device further comprises a firstintake fan taking gas into the protruding portion from a first intakeport formed on one surface of the protruding portion and a guidemechanism guiding the gas, which is taken into the protruding portion bythe first intake fan, into the base portion.

It is preferable that the first intake port is formed on a first sidesurface of the protruding portion facing the projection lens.

It is preferable that the housing includes a second side surface and athird side surface provided on the base portion, the second side surfacehas a same orientation as the first side surface, and the third sidesurface has an orientation opposite to an orientation of the first sidesurface, and the projection device further comprises a plurality ofexhaust fans discharging gas from a first exhaust port and a secondexhaust port formed on the second side surface and the third sidesurface, respectively.

It is preferable that the projection device further comprises aplurality of exhaust fans and, among the plurality of exhaust fans, anumber of rotations of at least one of the exhaust fans, which are farfrom the first intake fan, per unit time is larger than the number ofrotations of at least one of the exhaust fans, which are close to thefirst intake fan, per unit time.

It is preferable that an amount of gas to be taken in from the firstintake fan is larger than an average of amount of gas to be dischargedfrom the plurality of exhaust fans.

It is preferable that the housing includes a second side surface or athird side surface provided on the base portion, the second side surfacehas a same orientation as the first side surface, and the third sidesurface has an orientation opposite to an orientation of the first sidesurface, the projection lens includes a mechanism for changing aprojection direction of the image light, and the projection devicefurther comprise a variable mechanism changing an exhaust direction ofgas discharged from an exhaust port formed on the second side surface orthe third side surface in conjunction with the projection direction.

It is preferable that the projection device further comprises a secondintake fan taking gas into the protruding portion from a second intakeport formed on a fourth side surface intersecting the first side surfaceof the protruding portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a projector according to an embodiment.

FIG. 2 is a perspective view of the horizontally placed projector.

FIG. 3 is a perspective view of the vertically placed projector.

FIG. 4 is a diagram showing an aspect where the projector is used toproject an image onto a screen.

FIG. 5 is a plan view showing the schematic configuration of the insideof a body of the projector.

FIG. 6 is a side view showing a third side surface of the projector.

FIG. 7 is a side view showing first and second side surfaces of theprojector.

FIG. 8 is a perspective view showing the configuration of a first intakeport formed on the first side surface and a duct.

FIG. 9 is a diagram showing the flow of air inside a body part of theprojector.

FIG. 10 is a diagram illustrating a region of the protruding portionfacing a projection lens.

FIG. 11 is a diagram illustrating an example in which the design of aguide mechanism is changed.

FIG. 12 is a diagram illustrating a partition member that is an examplein which the design of a guide mechanism is changed.

FIG. 13 is a diagram showing the flow of air inside the body part of theprojector in a case where the partition member is provided as a guidemechanism.

FIG. 14 is a diagram illustrating another partition member that is anexample in which the design of a guide mechanism is changed.

FIG. 15 is a diagram illustrating the amount of air to be dischargedfrom an exhaust fan.

FIG. 16 is a diagram illustrating a distance between the exhaust fan anda first intake fan.

FIG. 17 is a plan view showing the schematic configuration of the insideof a body of a projector of an example in which design is changed.

FIG. 18 is a plan view showing the schematic configuration of the insideof a body of a projector of an example in which design is changed.

FIG. 19 is a block diagram showing the control configuration of alouver.

FIG. 20 is a diagram illustrating the projection direction of an imageand the orientation of the louver.

FIG. 21 is a diagram illustrating the projection direction of an imageand the orientation of the louver.

FIG. 22 is a plan view showing the schematic configuration of the insideof a body of a projector of an example in which design is changed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An example of an embodiment of a technique of the disclosure will bedescribed below with reference to the drawings.

Terms, such as “first”, “second”, and “third”, used in thisspecification are added to avoid the confusion of components and do notlimit the number of components present in a projector or a lens.

As shown in FIG. 1, a projector 10 according to an embodimentcorresponds to a projection device and comprises a projection lens 11and a body part 12. The body part 12 corresponds to a housing. One endportion of the projection lens 11 is mounted on the body part 12. FIG. 1shows a storage state where the projection lens 11 is stored in a casewhere the projector 10 is not in use.

The body part 12 comprises a base portion 12A and a protruding portion12B. The body part 12 houses main components, such as an image formingunit 20 (see FIG. 5) and a control board 22 (see FIG. 5).

The base portion 12A has a substantially rectangular shape that ishorizontally long in a plan view shown in FIG. 1. The protruding portion12B protrudes from one side (end portion) of the base portion 12A. Theprotruding portion 12B has a substantially rectangular shape, and thewidth of the protruding portion 12B is about a half of the length of oneside of the base portion 12A. For this reason, the body part 12 has asubstantially L-shape in a plan view as a whole including the baseportion 12A and the protruding portion 12B. The shape of the body partincluding the protruding portion 12B may not be a substantially L-shape.

The body part 12 includes a pair of main surfaces 13G and 13H having asubstantially L-shape (see FIG. 2). The pair of main surfaces 13G and13H corresponds to a top surface and a bottom surface in a case wherethe body part 12 is horizontally placed as shown in FIG. 2. A part ofeach of the main surfaces 13G and 13H forms the outer peripheral surfaceof the body part 12A, and the rest thereof forms the outer peripheralsurface of the protruding portion 12B.

Further, returning to FIG. 1, the body part 12 includes six sidesurfaces, that is, a first side surface 13A, a second side surface 13B,a third side surface 13C, a fourth side surface 13D, a fifth sidesurface 13E, and a sixth side surface 13F as side surfaces correspondingto the respective sides of the pair of main surfaces 13G and 13H havinga substantially L-shape.

Three surfaces of the first side surface 13A, the second side surface13B, and the third side surface 13C are substantially parallel to eachother. The first side surface 13A and the second side surface 13B havethe same orientation. The first side surface 13A forms one outerperipheral surface of the protruding portion 12B, and the second sidesurface 13B forms one outer peripheral surface of the base portion 12A.The third side surface 13C has an orientation opposite to theorientation of each of the first side surface 13A and the second sidesurface 13B. A portion 13C1, which is a part of the third side surface13C, forms one outer peripheral surface of the protruding portion 12Band a portion 13C2, which is the rest thereof, forms one outerperipheral surface of the base portion 12A. For example, the portion13C1 and the portion 13C2 of the third side surface 13C are continuouswith each other. The portion 13C1 and the portion 13C2 may not becontinuous with each other, or a groove or a step may be formed betweenthe portion 13C1 and the portion 13C2.

Three side surfaces, that is, the fourth side surface 13D, the fifthside surface 13E, and the sixth side surface 13F are orthogonal to threeside surfaces, that is, the first side surface 13A, the second sidesurface 13B, and the third side surface 13C. That is, in FIG. 1, thethree side surfaces, that is, the first side surface 13A, the secondside surface 13B, and the third side surface 13C are surfaces extendingin a vertical direction, and the three side surfaces, that is, thefourth side surface 13D, the fifth side surface 13E, and the sixth sidesurface 13F are surfaces extending in a horizontal direction.

The fourth side surface 13D and the fifth side surface 13E have the sameorientation. The fourth side surface 13D forms one outer peripheralsurface of the protruding portion 12B, and the fifth side surface 13Eforms one outer peripheral surface of the base portion 12A. The sixthside surface 13F has an orientation opposite to the orientation of eachof the fourth side surface 13D and the fifth side surface 13E. The sixthside surface 13F forms one outer peripheral surface of the base portion12A.

In other words, the body part 12, which is an example of the housing,comprises the second side surface 13B that has the same orientation asthe first side surface 13A, which is one surface of the protrudingportion 12B, on the base portion 12A and comprises the third sidesurface 13C that has an orientation opposite to the orientation of thefirst side surface 13A.

Further, the respective meanings of “the same orientation” and “oppositeorientations” in this specification are as follows in terms of therespective surfaces forming the outer periphery of the housing thatshows the body part 12 as an example. A fact that the respectivesurfaces have “the same orientation” means that an angle between outwardnormal vectors of the respective surfaces facing the outside of thehousing is 30° or less. Furthermore, in this specification, a fact thatthe respective surfaces have “opposite orientations” means that an anglebetween outward normal vectors of the respective surfaces facing theoutside of the housing is 150° or more. In the above-mentioned example,in a case where the first side surface 13A, the second side surface 13B,and the third side surface 13C are parallel to each other, an anglebetween the normal vectors of the first side surface 13A and the secondside surface 13B is 0° and an angle between the normal vectors of thefirst side surface 13A and the third side surface 13C is 180°. That is,the first side surface 13A, the second side surface 13B, and the thirdside surface 13C do not necessarily need to be parallel to each other,and an angle between the outward normal vectors of the respectivesurfaces has only to be in a range satisfying the above-mentioned range.

In FIG. 1, a space formed on the left side of the protruding portion 12Bis a space in which the projection lens 11 is to be disposed. Since thisspace is a space in which the appearance of the projection lens 11 beingnot in use is to be housed, this space will be referred to as a storageportion 12C storing the projection lens 11 for convenience in thisspecification. The storage portion 12C has a substantially rectangularshape in a plan view like the protruding portion 12B. That is, it isassumed that the fourth side surface 13D, which is an upper sidesurface, and the second side surface 13B, which is a left side surface,in FIG. 1 among the outer peripheral surfaces of the body part 12 extendin directions where the fourth side surface 13D and the second sidesurface 13B intersect each other. A space, which is defined using therespective extending side surfaces 13D and 13B as outer edges, is thestorage portion 12C. For this reason, the body part 12 has asubstantially L-shape by itself, but has a substantially rectangularshape in a plan view as a whole including the storage portion 12C.

In a case where the projector 10 is not in use, the projection lens 11is stored in the storage portion 12C after being transformed not toprotrude from the rectangular storage portion 12C.

Luminous flux representing an image formed by the image forming unit 20is incident on the projection lens 11 from the body part 12. Theprojection lens 11 enlarges image light, which is based on the incidentluminous flux, by an optical system and forms an image. Accordingly, theprojection lens 11 projects the enlarged image of the image, which isformed by the image forming unit 20, onto a screen S (see FIG. 4) thatis a projection target.

Since the projection lens 11 includes a bending optical system (seeFIGS. 2 and 3) for bending an optical axis twice by way of example, theprojection lens 11 has a substantially U-shape convex upward as a wholein the storage state shown in FIG. 1. The projection lens 11 comprisesan incident-side end part 14A, an intermediate part 14B, and anemission-side end part 14C. The incident-side end part 14A is connectedto one end of both ends of the intermediate part 14B, and theemission-side end part 14C is connected to the other end of both ends ofthe intermediate part 14B. Light emitted from the body part 12 isincident on the incident-side end part 14A. The emission-side end part14C is provided with an emission lens 16. Light, which is incident onthe incident-side end part 14A from the body part 12, is guided to theemission-side end part 14C through the intermediate part 14B. Theemission-side end part 14C emits light, which is guided from the bodypart 12 through the incident-side end part 14A and the intermediate part14B, to the screen S from the emission lens 16.

The projection lens 11 is disposed on one side of the base portion 12Ato face the protruding portion 12B, and the incident-side end part 14Ais mounted on the outer peripheral surface of the base portion 12A. Themounting position of the incident-side end part 14A is a positionadjacent to the protruding portion 12B in a horizontal direction in FIG.1, and is positioned near the middle of the base portion 12A. In thestorage state of the projection lens 11, the intermediate part 14Bextends from near the middle of the base portion 12A toward an endportion thereof opposite to the protruding portion 12B, that is, theleft side in FIG. 1.

As shown in FIGS. 2 and 3, the projection lens 11 comprises the bendingoptical system. The bending optical system has a first optical axis A1,a second optical axis A2, and a third optical axis A3. The secondoptical axis A2 is an optical axis that is bent at an angle of 90° fromthe first optical axis A1. The third optical axis A3 is an optical axisthat is bent at an angle of 90° from the second optical axis A2.

The incident-side end part 14A is non-rotatably mounted on the body part12. The intermediate part 14B is rotatable about the first optical axisAl with respect to the incident-side end part 14A. Since theemission-side end part 14C is connected to the intermediate part 14B,the emission-side end part 14C is also rotated about the first opticalaxis A1 in a case where the intermediate part 14B is rotated withrespect to the incident-side end part 14A. A rotatable range about thefirst optical axis A1 is 180° in this example. The incident-side endpart 14A may be rotatable with respect to the body part 12 instead ofthe intermediate part 14B.

Further, the emission-side end part 14C is rotatable about the secondoptical axis A2 with respect to the intermediate part 14B. The rotationof the emission-side end part 14C about the second optical axis A2 isnot limited and, for example, the emission-side end part 14C can also berotated at an angle of 360° or more.

As described above, the emission-side end part 14C is rotatable abouttwo axes, which are the first optical axis Al and the second opticalaxis A2, as rotation axes. The projection lens 11 is provided with arotational position detection sensor (not shown) that detects arotational position about the first optical axis Al and a rotationalposition about the second optical axis A2.

FIG. 2 shows a state where the projector 10 is horizontally placed on aninstallation surface 18, and FIG. 3 shows a state where the projector 10is vertically placed on the installation surface 18. As described above,the projector 10 can be used in a horizontal attitude and a verticalattitude.

As shown in FIG. 3, the fourth side surface 13D of the protrudingportion 12B is provided with an operation panel 17. The operation panel17 includes a plurality of operation switches. The operation switchesare, for example, a power switch, adjustment switches, and the like. Theadjustment switches are switches that are used to perform variousadjustments. The adjustment switches include, for example, switches thatare used to perform the image quality adjustment and keystone correctionof an image projected onto the screen S.

One surface of the intermediate part 14B of the projection lens 11 isprovided with a first unlock switch 19A and a second unlock switch 19B.The projection lens 11 is provided with a first rotation lockingmechanism and a second rotation locking mechanism. The first rotationlocking mechanism locks the rotation of the intermediate part 14B aboutthe first optical axis A1 with respect to the incident-side end part14A. The second rotation locking mechanism locks the rotation of theemission-side end part 14C about the second optical axis A2 with respectto the intermediate part 14B. The first unlock switch 19A is anoperation switch that inputs an instruction to unlock the rotation ofthe intermediate part 14B to the first rotation locking mechanism. Thesecond unlock switch 19B is an operation switch that inputs aninstruction to unlock the rotation of the emission-side end part 14C tothe second rotation locking mechanism.

Further, as shown in FIGS. 2 and 3, a power cable port 80 for a powercable and a video cable port 82 for a video cable are formed on thesecond side surface 13B of the base portion 12A. The video cableconnects the projector 10 to an external device, such as a personalcomputer outputting video signals. For example, a high-definitionmultimedia interface (HDMI: registered trademark) cable, a DigitalVisual Interface (DVI) cable, and a Video Graphics Array (VGA) cable canbe used as the type of the video cable.

The image forming unit 20 forms an image to be projected. As shown inFIG. 5, the image forming unit 20 includes a light source section 23, acolor separation section 24, and an image light generation section 25.

The light source section 23 is, for example, a white light source andsupplies white light to the color separation section 24. The colorseparation section 24 separates the white light, which is emitted fromthe light source section 23, into three types of color lightscorresponding to a red color, a green color, and a blue color. The colorlights, which are separated by the color separation section 24 tocorrespond to a red color, a green color, and a blue color, aremodulated to image lights, which have image information and correspondto the respective colors, that is, a red color, a green color, and ablue color, in the image light generation section 25. Then, therespective modulated color image lights are combined in the image lightgeneration section 25, so that image light having image informationcorresponding to three colors, that is, a red color, a green color, anda blue color is generated. This image light is incident on theprojection lens 11.

In this example, the light source section 23 includes a light emittingmodule 30, which includes semiconductor light-emitting elements, and alight combination section 31. The light emitting module 30 is a lightsource comprising semiconductor lasers, which emit blue light B as, forexample, laser light, as the semiconductor light-emitting elements. Thesemiconductor laser is an example of a semiconductor light sourceaccording to the technique of the disclosure. The light combinationsection 31 comprises a polarization separation element 32, aquarter-wave plate 34, a mirror 35, and a phosphor wheel 36. Thephosphor wheel 36 includes, for example, a phosphor that is excited byblue light B and emits yellow light Y. That is, the phosphor wheel 36functions as a wavelength conversion element that converts blue light Binto yellow light Y having a wavelength longer than the wavelength ofblue light B. In this example, the light combination section 31 convertsa part of blue light B into yellow light Y and combines blue light Bwith yellow light Y to generate white light W.

Blue light B emitted from the light emitting module 30 is incident onthe polarization separation element 32 of the light combination section31. The polarization separation element 32 is disposed to form an angleof 45° with respect to the optical axis. The polarization separationelement 32 has a polarization separation function that separatesincident blue light B into S-polarized light components and P-polarizedlight components with respect to the polarization separation element 32.The polarization separation element 32 reflects S-polarized lightcomponents and transmits P-polarized light components. Further, in thisembodiment, the polarization separation element 32 has wavelengthselectivity and transmits light, which has a wavelength range differentfrom the wavelength range of blue light, regardless of the polarizationstate of the light.

P-polarized blue light B_(P) transmitted through the polarizationseparation element 32 is converted into circularly polarized light, forexample, right-handed circularly polarized blue light Br by beingtransmitted through the quarter-wave plate 34, and is then incident onthe mirror 35. In this case, the mirror 35 reflects the right-handedcircularly polarized blue light Br as left-handed circularly polarizedblue light Be. The left-handed circularly polarized blue light Bereflected by the mirror 35 is converted into S-polarized blue light Bs2by being transmitted through the quarter-wave plate 34 again. TheS-polarized blue light Bs2 is reflected by the polarization separationelement 32 and travels toward the color separation section 24.

On the other hand, S-polarized blue light Bs1 reflected by thepolarization separation element 32 is incident on the phosphor wheel 36.The phosphor wheel 36 includes a phosphor layer 37 that is formed on adisc in a ring shape and a motor 38 that rotates the disc. The phosphorwheel 36 is rotated so that incident positions where the blue light Bs1is to be incident are not concentrated on one place. Since heat isgenerated at the incident positions of the blue light Bs1,heat-generating portions are dispersed in a case where the phosphorwheel 36 is rotated.

The phosphor layer 37 contains phosphor particles that absorb the bluelight Bs1 as excitation light, convert the blue light Bs1 into yellowfluorescence (hereinafter, referred to as yellow light) Y, and emit theyellow fluorescence. For example, an yttrium aluminum garnet (YAG)-basedphosphor can be used as the phosphor particles. A material used to makethe phosphor particles may be one type of material, or a material intowhich particles made of two or more types of materials are mixed may beused as phosphor particles.

Since the surface of the disc is a reflective surface, the yellow lightY generated by the phosphor layer 37 is reflected toward thepolarization separation element 32. The yellow light Y is transmittedthrough the polarization separation element 32 and travels toward thecolor separation section 24. The yellow light Y transmitted through thepolarization separation element 32 is combined with the blue light Bs2reflected by the polarization separation element 32, so that white lightW is generated.

The light emitting module 30 may be adapted to include a light emittingelement array in which a plurality of semiconductor lasers are arrangedtwo-dimensionally. For example, a light source device disclosed inJP2018-21990A can be used as the light source section 23.

The white light W generated by the light source section 23 as describedabove is supplied to the color separation section 24 as irradiationlight. The color separation section 24 comprises two dichroic mirrors 40and 42 and three mirrors 44, 46, and 48. The color separation section 24separates the irradiation light, which is emitted from the light sourcesection 23, into color lights corresponding to three colors, that is, ared color, a green color, and a blue color by the two dichroic mirrors40 and 42. Further, the color separation section 24 also functions as alight guide member that guides each color light to the image lightgeneration section 25.

The dichroic mirror 40 is disposed on the optical path of theirradiation light that is supplied from the light source section 23.Further, the dichroic mirror 40 is formed in a substantially plate shapeand is disposed in an attitude in which the dichroic mirror 40 is tiltedat an angle of about 45° with respect to the optical axis of theirradiation light. Since the dichroic mirror 40 has properties in whichred light is reflected and green light and blue light are transmitted,the dichroic mirror 40 reflects only red light components of theirradiation light, which is white light, and transmits green lightcomponents and blue light components.

The red light reflected by the dichroic mirror 40 is reflected by themirror 44 and travels toward the image light generation section 25. Onthe other hand, the green light and the blue light transmitted throughthe dichroic mirror 40 travel toward the dichroic mirror 42.

Like the dichroic mirror 40, the dichroic mirror 42 is formed in asubstantially plate shape and is disposed in an attitude in which thedichroic mirror 42 is tilted at an angle of about 45° with respect tothe optical axis of the irradiation light. Since the dichroic mirror 42has properties in which green light is reflected and blue light istransmitted, the dichroic mirror 42 reflects the green light componentsof the irradiation light including the green light components and theblue light components transmitted through the dichroic mirror 40 andtransmits the blue light components thereof

The green light reflected by the dichroic mirror 42 travels toward theimage light generation section 25. On the other hand, the blue lighttransmitted through the dichroic mirror 42 travels toward the mirror 46.Like the dichroic mirrors 40 and 42, the mirror 46 is formed in asubstantially plate shape and is provided to be tilted at an angle ofabout 45° with respect to the optical axis of the irradiation light. Theblue light reflected by the mirror 46 travels toward the mirror 48. Themirror 48 is provided to be tilted at an angle of about 45° with respectto the optical axis of the blue light that is reflected by the mirror46. The blue light is reflected by the mirror 48 and travels toward theimage light generation section 25.

The image light generation section 25 includes an LCD 50 for red light,an LCD 52 for green light, an LCD 54 for blue light, and a crossdichroic prism 56. The three LCDs 50, 52, and 54 are arranged to facethree side surfaces of the cross dichroic prism 56, respectively. Inthis example, among the three LCDs 50, 52, and 54, the LCD 50 for redlight and the LCD 54 for blue light face two side surfaces of the crossdichroic prism 56 facing each other. That is, the LCD 50 for red lightand the LCD 54 for blue light are arranged to face each other with thecross dichroic prism 56 interposed therebetween. Further, the LCD 52 forgreen light is orthogonal to the two side surfaces of the cross dichroicprism 56 that face the two LCDs 50 and 54, and is disposed to face oneside surface of which both sides are in contact with the respective twoside surfaces.

Among the color lights corresponding to three colors that are separatedin the color separation section 24, the red light travels toward the LCD50 for red light, the green light travels toward the LCD 52 for greenlight, and the blue light travels toward the LCD 54 for blue light.

Each of the LCD 50 for red light, the LCD 52 for green light, and theLCD 54 for blue light is, for example, a transmission type LCD, and isan example of an image forming panel.

The LCD 50 for red light modulates red light to be transmitted togenerate red image light having image information of a red component.The red image light generated by the LCD 50 for red light is incident onthe cross dichroic prism 56.

The LCD 52 for green light modulates green light to be transmitted togenerate green image light having image information of a greencomponent. The green image light generated by the LCD 52 for green lightis incident on the cross dichroic prism 56. Likewise, the LCD 54 forblue light modulates blue light to be transmitted to generate blue imagelight having image information of a blue component. The blue image lightgenerated by the LCD 54 for blue light is incident on the cross dichroicprism 56.

The cross dichroic prism 56 is formed in a substantially cubic shapeusing a transparent material, such as glass, and includes dichroicsurfaces 56 a and 56 b, which intersect each other, therein. Thedichroic surface 56 b has properties in which red light is reflected andgreen light and blue light are transmitted. The dichroic surface 56 ahas properties in which blue light is reflected and red light and greenlight are transmitted.

The cross dichroic prism 56 is disposed to face the incident-side endpart 14A of the projection lens 11. The red image light incident on thecross dichroic prism 56 is reflected by the dichroic surface 56 b and isincident on the projection lens 11. The green image light is transmittedthrough each of the dichroic surfaces 56 a and 56 b and is incident onthe projection lens 11. Further, the blue image light is reflected bythe dichroic surface 56 a and is incident on the projection lens 11.

As described above, the cross dichroic prism 56 integrates therespective incident color image lights to generate image light havingimage information corresponding to three colors, that is, a red color, agreen color, and a blue color, and causes the generated image light tobe incident on the projection lens 11. The projection lens 11 projectsthe image light, which has the image information corresponding to threecolors, that is, a red color, a green color, and a blue color, onto thescreen S. Accordingly, a full color image is displayed on the screen S.

As shown in FIG. 5, the control board 22 is provided in the body part 12to be close to the second side surface 13B of the base portion 12A. Thecontrol board 22 comprises a control circuit. An example of the controlcircuit (processor) is a central processing unit (CPU). The controlcircuit includes a controller that controls the operation of theprojection device and a drive circuit that drives the three LCDs 50, 52,and 54. Further, the control board 22 is also provided with a powersource circuit and the like. The power source circuit includes analternating current (AC)-direct current (DC) converter that converts anAC voltage supplied from a commercial power source into a DC voltage, aDC-DC converter that adjusts a DC drive voltage to be supplied to eachinternal part, and the like.

As already described, the second side surface 13B of the base portion12A is provided with a power cable port 80 (see FIG. 2) that iselectrically connected to the power source circuit. A power cable isconnected to this power cable port 80. Accordingly, power supplied fromthe outside is supplied to the control board 22 through the power cable.The control board 22 is disposed to partially overlap with the imageforming unit 20 in a plan view in this embodiment, but does notnecessarily need to overlap with the image forming unit 20.

The light source section 23 comprises the light emitting module 30. Thelight emitting module 30 generates heat as the lasers emit light. Thephosphor wheel 36 generates heat as laser light emitted from the lightemitting module 30 is incident on the phosphor wheel 36. Further, theimage light generation section 25 generates heat due to the drive of theLCDs 50, 52, and 54. Since the respective color image lights transmittedthrough the respective LCDs 50, 52, and 54 are incident on the crossdichroic prism 56 including surfaces facing the three LCDs 50, 52, and54 for the respective colors lights, the cross dichroic prism 56generates heat. Furthermore, various optical elements, such as theabove-mentioned dichroic mirrors 40 and 42 where high-power laser lightis reflected or transmitted, also generate heat. In addition, the powersource circuit and the like of the control board 22 also generate heat.

Among these heat sources provided in the body part 12, the lightemitting module 30, the image light generation section 25, and thephosphor wheel 36 are main heat sources that have a relatively largeamount of heat to be generated. It is preferable that these membersserving as heat sources are arranged in the body part 12 at a certaindistance therebetween without being close to each other. The reason forthis is that the cooling effects of the respective heat sources areimproved since an influence of heat between the respective heat sourcescan be more easily reduced as an interval between the respective heatsources is longer.

First, the light emitting module 30 is disposed in the protrudingportion 12B. The protruding portion 12B protrudes from a substantiallyright half region of the base portion 12A in FIG. 5. The projection lens11 is disposed to face the protruding portion 12B, and is mounted on theouter peripheral surface of the base portion 12A. In a case where theprotruding portion 12B is disposed in a substantially right half regionof the base portion 12A as in this example, the projection lens 11 ispositioned in a substantially left half region thereof in FIG. 5.

The cross dichroic prism 56 is disposed in the base portion 12A to facethe incident-side end part 14A of the projection lens 11. As describedabove, the LCDs 50, 52, and 54 for the respective color lights, that is,a red color, a green color, and a blue color are arranged to correspondto three side surfaces of the cross dichroic prism 56. Here, the crossdichroic prism 56 corresponds to a “prism” according to the technique ofthe disclosure.

According to the above-mentioned arrangement, two heat sources, that is,the light emitting module 30 that includes the semiconductor lasers asan example of the semiconductor light source and the image lightgeneration section 25 that includes the cross dichroic prism 56 as anexample of a prism and the LCDs 50, 52, and 54 for the respective colorlights as an example of electro-optical elements can be spaced from eachother in the body part 12 having an L-shape in a plan view. For thisreason, the temperature rise of each heat source is likely to besuppressed in the projection device according to this embodiment ascompared to, for example, a case where both the light emitting module 30and the image light generation section 25 are provided in the baseportion 12A.

Further, the laser light emitted from the light emitting module 30 needsto be incident on the LCDs 50, 52, and 54 after passing through thelight combination section 31 and the color separation section 24, andparticularly a distance between each of the LCDs 50 and 52 and the lightemitting module 30 is short. Furthermore, the light of the semiconductorlight source, which is represented by laser light, is light of which theparallelism is high and the width of an optical path is difficult to beincreased. Accordingly, a length sufficient to arrange the plurality ofoptical elements included in the light combination section 31 and thecolor separation section 24 is required as an optical path length toeach of the LCDs 50 and 52 from the light emitting module 30 includingthe semiconductor light source. Since the light emitting module 30including the semiconductor light source is provided in the protrudingportion 12B, an optical path length to the image light generationsection 25, which is disposed in the base portion 12A, from the lightemitting module 30 is likely to be increased. In a case where the imagelight generation section 25 uses the three LCDs 50, 52, and 54 for therespective color lights as the plurality of electro-optical elements asin this example, the color separation section 24 that separates whitelight into each color light is often needed. In that case, the pluralityof mirrors of the color separation section 24 need to be arranged in theoptical path. For this reason, the configuration where the lightemitting module 30 and the image light generation section 25 are spacedfrom each other as described above is particularly effective in a casewhere a plurality of electro-optical elements for each color are used.

In addition, the configuration where the light emitting module 30 andthe image light generation section 25 are spaced from each other asdescribed above is particularly effective in a case where thesemiconductor light source is semiconductor lasers as in this example.The reason for this is that laser light emitted from the semiconductorlaser has directivity higher than that of the light emitted from a lightemitting diode and has a divergence angle smaller than that of the lightemitted from a light emitting diode. Further, the reason for this isthat it is necessary to increase a divergence angle in order to increasethe angle of view of image light to be projected onto the screen, but alonger optical path length needs to be ensured in the case of thesemiconductor laser than in the case of the light emitting diode forthat purpose.

Further, the phosphor wheel 36, which is an example of a wavelengthconversion element, is provided in the base portion 12A. Since the lightemitting module 30 is provided in the protruding portion 12B and thephosphor wheel 36 is disposed in the base portion 12A, both the lightemitting module 30 and the phosphor wheel 36 can be spaced from eachother. Not only the light emitting module 30 but also the phosphor wheel36 is a main heat source. For this reason, since heat sources arearranged to be dispersed as compared to, for example, a case where boththe light emitting module 30 and the phosphor wheel 36 are provided inthe base portion 12A, the temperature rise of each heat source is likelyto be suppressed.

In this example, the phosphor wheel 36 is disposed to be close to thethird side surface 13C, which is closer to the protruding portion 12B,of two side surfaces of the base portion 12A facing each other, that is,the second side surface 13B and the third side surface 13C. Further, theimage light generation section 25 is disposed near the middle of thebase portion 12A in this example. For this reason, since the phosphorwheel 36 is disposed in the base portion 12A to be close to the sidesurface closer to the protruding portion 12B, the phosphor wheel 36 andthe image light generation section 25 can also be spaced from eachother.

Furthermore, the power source circuit and the like of the control board22 generate heat as described above. In this example, the control board22 is disposed to be close to the second side surface 13B, which isfarther from the protruding portion 12B, of two side surfaces of thebase portion 12A facing each other, that is, the second side surface 13Band the third side surface 13C. Accordingly, the control board 22 andthe light emitting module 30 can be spaced from each other.

Here, the side surface, which is closer to the protruding portion 12B,of two side surfaces facing each other, that is, the second side surface13B and the third side surface 13C means a side surface positioned on aside (a right side shown in FIG. 5), on which the protruding portion 12Bis provided, of the center of the base portion 12A in a width direction(a horizontal direction shown in FIG. 5) in a plan view. Likewise, theside surface, which is farther from the protruding portion 12B, means aside surface positioned on a side (a left side shown in FIG. 5), onwhich the protruding portion 12B is not provided, of the center of thebase portion 12A in the width direction (the horizontal direction shownin FIG. 5) in a plan view shown in FIG. 5.

Since the light emitting module 30, the image light generation section25, and the phosphor wheel 36, which are main heat sources, are arrangedin the body part 12 having an L-shape in a plan view to be dispersed asdescribed above, the plurality of main heat sources can be spaced fromeach other. Accordingly, the temperature rise of each heat source islikely to be suppressed in the projector 10 according to this embodimentas compared to, for example, a case where all the plurality of main heatsources are arranged in the base portion 12A to be close to each other.

In addition, the projector 10 comprises an intake/exhaust mechanism tocool the plurality of heat sources provided in the body part 12A inaddition to devise the arrangement of the plurality of the main heatsources.

The intake/exhaust mechanism will be described below. FIG. 6 is a viewof the body part seen from the left side in FIG. 5, and FIG. 7 is a viewof the body part seen from the right side in FIG. 5. However, FIG. 6shows a state where the projection lens 11 is removed from the body part12.

As shown in FIGS. 5 to 7, the projector 10 comprises a first intake port60 provided on the first side surface 13A of the protruding portion 12B.As described above, the first side surface 13A of the protruding portion12B is a surface facing the projection lens 11. Further, the projector10 comprises a first intake fan 62 that is provided in the protrudingportion 12B to face the first intake port 60 and takes in air as gasinto the protruding portion 12B from the first intake port 60.Furthermore, the projector 10 comprises a duct 64 as a guide mechanismthat guides air taken in by the first intake fan 62 into the baseportion 12A.

The duct 64 is disposed to guide at least a part of air, which is takenin by the first intake fan 62, to the base portion 12A. In thisembodiment, the duct 64 is disposed as shown in FIG. 8 so that oneopening 64 a of the duct 64 covers about a half of the surface of theintake fan 62 and the other opening 64 b faces the base portion 12A.

As shown by broken-line arrows in FIG. 8, air is taken in from the firstintake port 60 by the intake fan and is supplied into the protrudingportion 12B. In this case, a part of the air is supplied into the duct64 from one opening 64 a of the duct 64 and is discharged from the otheropening 64 b through the duct 64. In this case, since the opening 64 bfaces the base portion 12A, air passing through the duct 64 isdischarged to the base portion 12A. On the other hand, the other part ofthe air taken in from the first intake port 60 flows into the protrudingportion 12B as it is without being supplied to the duct 64. The reasonwhy the opening 64 a of the duct 64 is disposed to cover only about ahalf of the surface of the intake fan 62 is to supply cooling air to thelight emitting module 30 positioned in the protruding portion 12B. In acase where a heat source, such as the light emitting module 30, is notdisposed in the protruding portion 12B, the opening 64 a of the duct 64may be adapted to cover the entire intake fan 62 and to discharge allthe taken air to the base portion 12A.

Further, as shown in FIG. 5, the projector 10 comprises a first exhaustport 70 provided on the second side surface 13B of the base portion 12Aand comprises a second exhaust port 74 provided on the third sidesurface 13C. Furthermore, the projector 10 comprises a plurality ofexhaust fans 72 a, 72 b, 76 a, 76 b, and 76 c that discharges air fromthe first exhaust port 70 and the second exhaust port 74, respectively.Specifically, the projector 10 comprises two first exhaust fans 72 a and72 b that are provided in the base portion 12A to face the first exhaustport 70. Further, the projector 10 comprises three second exhaust fans76 a, 76 b, and 76 c that are provided in the protruding portion 12B andthe base portion 12A to face the second exhaust port 74.

In this example, for example, porous members 60 a, 70 a, and 74 a, suchas punching metals in which a plurality of small holes are formed, areinstalled in the intake port 60 and the two exhaust ports 70 and 74,respectively. The shape of the hole formed in the porous member may beany shape, such as an elliptical shape and a polygonal shape, withoutbeing limited to a circular shape, and the number of the holes is alsonot limited. Further, the intake port and the exhaust ports may beformed of a plurality of small holes that are formed on the surfacesthemselves of the housing.

The flow of air in the body part 12 is shown in FIG. 9 by arrows. Asalready described, the air taken in from the first intake port 60 istaken into the protruding portion, a part of the air is supplied intothe base portion 12A through the duct 64, and a part of the air issupplied to the central portion of the protruding portion 12B as it is.The air guided to the base portion 12A from the duct 64 flows to theimage light generation section 25, the color separation section 24, andthe light combination section 31 of the light source section 23 andcools the respective sections. After that, the air present in the baseportion 12A is discharged from the first exhaust port 70 and the secondexhaust port 74.

According to one embodiment of the technique of the disclosure, theprojector 10 comprises the first intake port 60 provided on theprotruding portion 12B of the housing comprising the base portion 12Aand the protruding portion 12B, and comprises the duct 64 that is anexample of a guide mechanism for guiding the air, which is taken intothe protruding portion 12B by the first intake fan 62, into the baseportion 12A. With this configuration, the air taken in from the outsidecan be supplied to the image light generation section 25, the colorseparation section 24, the light combination section 31, and the likethat are arranged in the base portion 12A. The temperature of the airtaken in from the outside is lower than the temperature of the airpresent in the body part 12. Accordingly, the air is taken into the bodypart 12 from the outside, so that various heat sources, such as theimage light generation section 25, the color separation section 24, thelight combination section 31, and the power source circuit of thecontrol board 22, can be cooled.

The body part 12, which is an example of the housing, is formed of thebase portion 12A and the protruding portion 12B that protrudes from onesurface of the base portion 12A, and has an L-shape as a whole in a planview. For this reason, in appearance, the protruding portion 12B looksas if a part of the base portion 12A protrudes. With regard to theinside of the body part 12, the inside of the protruding portion 12B isformed in the shape of a bag which is a dead end and through which aircannot pass in a case where the inside of the protruding portion 12B isseen from the base portion 12A. In this case, it is difficult to supplyair to the protruding portion 12B by merely taking in air from the baseportion 12A without providing an intake port on the protruding portion12B. According to the technique of the disclosure, air is taken in fromthe intake port provided on the protruding portion 12B and the taken aircan be supplied to the base portion 12A by the guide mechanism.Accordingly, even in a case where the body part 12, which is an exampleof the housing, has an L-shape in a plan view, the air can bedistributed to the entire inside of the body part 12 as compared to acase where the protruding portion 12B is not provided with an intakeport. Even in a case where the housing has an L-shape in a plan view,the cooling effects of the plurality of heat sources arranged in thehousing to be dispersed can be improved.

Further, in this example, the control board 22 is disposed to be closeto the second side surface 13B of the base portion 12A. The controlboard 22 is provided with the power source circuit and the power sourcecircuit is one of the main heat sources. For this reason, in a casewhere outside air is adapted to be taken in from the second side surface13B, the taken outside air is warmed by the heat of the control board 22and the wormed air is supplied to each portion of the base portion 12A.In this case, the cooling effect of the power source circuit is high,but there is a concern that the cooling effects of the other heatsources will be significantly lowered. In a case where outside air istaken in from the protruding portion 12B and the taken air is guided tothe base portion 12A by the guide mechanism as in this example, it ispossible to supply air to the base portion 12A while avoiding theinfluence of a heat source on a temperature rise. For this reason, theheat sources provided at the respective portions of the base portion 12Acan be relatively evenly cooled.

In addition, the first intake port 60 is formed on the first sidesurface 13A facing the projection lens 11 as shown in FIG. 9 in thisexample. As a result, the first side surface 13A is positioned near themiddle of the base portion 12A in the horizontal direction in FIG. 9.Further, air taken in from the first side surface 13A is guided to thebase portion 12A by the duct 64. Since the first side surface 13A ispositioned near the middle, air for cooling is likely to be supplied tothe vicinity of the middle of the base portion 12A through the duct 64.For this reason, the cooling effect of a heat source disposed near themiddle of the base portion 12A is high as compared to, for example, acase where air is supplied from both side surfaces of the base portion12A. The reason for this is that a distance to the heat source disposednear the middle of the base portion 12A from the intake port can beshortened. Since the image light generation section 25 is disposed nearthe middle of the base portion 12A in this example, the cooling effectof the image light generation section 25 can be improved.

For example, a method including disposing the first intake port 60 onthe third side surface 13C of the protruding portion 12B and lengtheningthe duct 64 to dispose the opening 64 b near the middle of the baseportion 12A is also considered as a method of supplying outside air,which is taken in from the protruding portion 12B, to the base portion12A. Even in this case, the projector 10 can guide air for cooling tothe vicinity of the middle of the base portion 12A. However, in a casewhere the first side surface 13A is provided with the first intake port60 as in this example, air for cooling can be guided to the vicinity ofthe middle of the base portion 12A without an increase in the length ofthe duct 64. For this reason, a space in which a long duct is to bedisposed can be reduced. Intake efficiency is higher as the duct isshorter.

Since the first intake port 60 is the shadow of the projection lens 11in a case where the first intake port 60 is formed on the first sidesurface 13A as in this example, the intrusion of dust and dirt from thefirst intake port 60 can be suppressed by the projection lens 11.Further, since the first intake port 60 is the shadow of the projectionlens 11, the first intake port 60 is difficult to be visually recognizedfrom the outside. As a result, the body part 12 having a neat appearanceis obtained. There is also a method including providing intake ports atpositions facing the image light generation section 25 on the mainsurfaces 13G and 13H of the base portion 12A as a method of introducingoutside air to the vicinity of the middle of the base portion 12A.However, in a case where the main surfaces 13G and 13H are provided withintake ports, there is a problem that the designability of appearance isimpaired. In a case where the first intake port 60 is formed on thefirst side surface 13A as in this example, outside air is likely to beintroduced to the vicinity of the middle of the base portion 12A while areduction in the designability of appearance is suppressed.

Further, in this example, in the body part 12 that is an example of thehousing, the second side surface 13B, which has the same orientation asthe first side surface 13A, is provided with the first exhaust port 70and the third side surface 13C, which has an orientation opposite to theorientation of the first side surface 13A, is provided with the secondexhaust port 74. For this reason, air taken in from the first intakeport 60 can flow in the horizontal direction of the base portion 12Ashown in FIG. 9 in the body part 12. Accordingly, air for cooling can beevenly distributed in the body part 12. Furthermore, in the body part12, surfaces, which have different orientations, are provided with thefirst exhaust port 70 and the second exhaust port 74, respectively.Accordingly, air can be discharged smoothly without being stayed in thebody part 12 as compared to a case where only one surface is providedwith an exhaust port. It can be expected that the amount oflow-temperature outside air to be taken in per unit time is alsoincreased in a case where air is discharged smoothly. Accordingly, acooling effect can be improved.

Modification Example of Disposition of First Intake Port

An example in which the first intake port 60 provided on the protrudingportion 12B is formed on the first side surface 13A has been describedin the above-mentioned example, but a surface on which the first intakeport 60 is formed is not limited to the first side surface 13A and theother surface of the protruding portion 12B may be provided with thefirst intake port 60. As long as the first intake port 60 is formed onthe protruding portion 12B even though the first intake port 60 is notformed on the first side surface 13A, outside air taken in from theprotruding portion 12B can be supplied to the base portion 12A by theguide mechanism of which an example is shown as the duct 64. For thisreason, even in a case where the housing of which an example is shown asthe body part 12 has an L-shape in a plan view, an effect of improvingthe cooling effect of the plurality of heat sources arranged in thehousing to be dispersed is obtained.

Further, an example in which the first side surface 13A is furtherprovided with the first intake port 60 for the purpose of facilitatingthe supply of air for cooling to the vicinity of the middle of the baseportion 12A has been described in the above-mentioned example. However,the first side surface 13A does not necessarily need to be provided withthe first intake port 60 in order to obtain the same effects.

For example, as long as the first intake port 60 is formed in a regionof the protruding portion 12B close to the projection lens 11, the sameeffects as in a case where the first side surface 13A is provided withthe first intake port 60 can be obtained. The region of the protrudingportion 12B facing the projection lens 11 is a region shown by hatchingwith diagonal lines in FIG. 10. This region is a region of theprotruding portion 12B that is closer to the projection lens 11 than themiddle of a distance D between a position closest to the projection lens11 and a position farthest from the projection lens 11. Such a region isclose to the vicinity of the middle of the base portion 12A in theprotruding portion 12B. For this reason, as long as the first intakeport 60 is provided in the region facing the projection lens 11, whichis shown by hatching in FIG. 10, other than the first side surface 13A,the same effects as in a case where the first side surface 13A isprovided with the first intake port 60 can be expected.

Of course, since the first side surface 13A is a surface that is theshadow of the projection lens 11 as described above, various effects,such as an effect of suppressing the entry of dust and dirt and aneffect of suppressing the deterioration of the designability ofappearance, are obtained in a case where the first side surface 13A isprovided with the first intake port 60. For this reason, consideringsuch a viewpoint, it is more preferable that a surface to be providedwith the first intake port 60 is the first side surface 13A.

Modification Example 1 of Guide Mechanism

The image forming unit 20 including the light source section 23, thecolor separation section 24, and the image light generation section 25may be integrally stored in an enclosure in the body part 12. In such acase, it is preferable that the guide mechanism is adapted to guide air,which is taken in from the first intake port 60, to two main surfaces,which face each other, of the enclosure provided in the base portion12A. Here, the two main surfaces, which face each other, of theenclosure are surfaces facing the two main surfaces 13G and 13H of thebody part 12, which face each other, respectively. The areas of the twomain surfaces, which face each other, of the enclosure are larger thanthe areas of the side surfaces that are in contact with the sides of themain surfaces, respectively. For this reason, in a case where the twomain surfaces are cooled, the image forming unit 20 provided in theenclosure can be cooled as a whole.

Specifically, the use of a duct 164, which is an example of the guidemechanism, is considered as shown in FIG. 11. The duct 164 has a shapewhere an end portion of the duct 164 facing the base portion 12A isformed to bifurcate, includes two openings 164 b separated from eachother in a vertical direction, and guides air taken in from an opening164 a facing the first intake port to both the main surfaces of the baseportion 12A. Accordingly, since air is blown to both main surfaces ofthe image forming unit 20 stored in the enclosure, the entire imageforming unit 20 can be cooled as a whole.

Modification Example 2 of Guide Mechanism

The ducts 64 and 164 have been described as the guide mechanism by wayof example in the above-mentioned examples, but the guide mechanism isnot limited to a tubular member, such as a duct. For example, apartition member provided in the housing is considered as an example ofthe guide mechanism other than the duct. For example, a partition plate66 that is a plate-like partition member provided in the protrudingportion 12B shown in FIG. 12 is used as the partition member. Thepartition plate 66 shown in FIG. 12 has the shape of a crank of whichboth ends are bent at an angle of 90° to have opposite orientations.However, the partition plate 66 may have only to be adapted to guide atleast a part of air, which is taken in by the first intake fan 62, tothe base portion 12A, and may have, for example, an L-shape and thelike.

Even in a case where the partition plate 66 is provided as the guidemechanism, the same flow of air as in a case where the duct 64 isprovided is generated as shown in FIG. 13 and the cooling effects of theheat sources arranged in the base portion 12A are improved.

Further, the guide mechanism may be a partition plate 68 shown in FIG.14. The partition plate 68 is provided with openings 68 a, and causes apart of air, which is taken in by the intake fan 62, to pass and to flowinto the protruding portion 12B and guides the other part of the air tothe base portion 12A. Even in a case where the partition plate 68 isprovided, substantially the same flow of air as in a case where the duct64 is provided is generated and the cooling effects of the heat sourcesarranged in the base portion 12A are improved.

Whether or not the guide mechanism is formed of the duct or thepartition member is appropriately determined in consideration of aspace, the layout of the respective components, and the like in the bodypart 12.

As for the Amount of Air to be Discharged

In the projector 10 according to this embodiment described withreference to FIGS. 1 to 9, the amounts E1 a, E1 b, E2 a, E2 b, and E3 bof air to be discharged from the plurality of exhaust fans 72 a, 72 b,76 a, 76 b, and 76 c may be equal to each other. On the other hand, asshown in FIG. 15, among the plurality of exhaust fans, the number ofrotations of the exhaust fan, which is far from the first intake fan 62,per unit time may be set to be larger than the number of rotations ofthe exhaust fan, which is close to the first intake fan 62, per unittime. Accordingly, the flow of air taken in from the first intake fan 62is likely to spread to a position away from the first intake fan 62. Ina case where two exhaust fans are provided, air is difficult to reachthe exhaust fan since the amount of air drawn to the position of theexhaust fan is smaller as an exhaust fan is farther. Accordingly, in acase where the number of rotations of the exhaust fan far from the firstintake fan is set to be large, a reduction in the amount of air to bedrawn can be suppressed. Therefore, the amounts of air to be dischargedfrom the respective exhaust fans can be made uniform. The plurality ofexhaust fans have different distances from the first intake fan 62, butmay include an exhaust fan group of which exhaust fans have the samenumber of rotations per unit time. Further, the size of a fan (blade) ofa specific exhaust fan may be increased as another means for increasingthe amount of air to be discharged from the specific exhaust fan.

A distance between the first intake fan 62 and each of the exhaust fans72 a, 72 b, 76 a, 76 b, and 76 c will be described with reference toFIG. 16.

In a plan view shown in FIG. 16, with regard to exhaust fans, such asthe second exhaust fans 76 a, 76 b, and 76 c, in which the entire linesegment connecting the center of the first intake fan 62 to the centerof the exhaust fan is present in the housing, the length of the linesegment is defined as a distance between the exhaust fan and the firstintake fan 62. On the other hand, in a case where a part of a linesegment connecting the center of the first intake fan 62 to the centerof an exhaust fan is out of the housing as in the first exhaust fans 72a and 72 b, the distance is defined as follows. First, an intersection Pbetween the extension line of the surface of the first intake fan 62,which faces the inside of the housing, and a boundary line between theprotruding portion 12B and the base portion 12A is obtained. Then, thesum of the length of a line segment connecting the intersection P to thecenter of the first intake fan 62 and the length of a line segmentconnecting the intersection P to the center of the exhaust fan isdefined as a distance between the exhaust fan and the first intake fan62.

As shown in FIG. 16, a distance between the first intake fan 62 and thesecond exhaust fan 76 a is denoted by L2 a, a distance between the firstintake fan 62 and the second exhaust fan 76 b is denoted by L2 b, and adistance between the first intake fan 62 and the second exhaust fan 76 cis denoted by L2 c. Further, a distance between the first intake fan 62and the first exhaust fan 72 a is denoted by L1 a, and a distancebetween the first intake fan 62 and the first exhaust fan 72 b isdenoted by L1 b. Here, the respective distances satisfy a relationshipof “L2 a<L2 b<L2 c<L1 a<L1 b”.

Assuming that the numbers and shapes (including thicknesses) of bladesare substantially the same, in a case where the plurality of exhaustfans have the same diameter, the amount of air to be discharged islarger as the number of rotations of the exhaust fan per unit time islarger. Here, the numbers of rotations of the first exhaust fans 72 aand 72 b are denoted by R1a and R1b, respectively, and the numbers ofrotations of the second exhaust fans 76 a, 76 b, and 76 c are denoted byR2a, R2b, and R2c, respectively. In this case, a relationship of“R2a<R2b<R2c<R1a<R1b” is set so that the number of rotations of anexhaust fan is larger as the exhaust fan is farther from the firstintake fan.

Further, in a case where the number of blades of the exhaust fan and theshape of the blade of the exhaust fan are changed or the diameter of theexhaust fan is changed, the amount of air to be discharged from theexhaust fan can be changed. Accordingly, as a distance from the firstintake fan is longer, an exhaust fan of which the number of blades, theshape of the blade, and the diameter is changed and which discharges alarger amount of air can also be disposed to realize the above-mentionedrelationship of the amount of air to be discharged.

Furthermore, in a case where the number of intake fans is smaller thanthe number of exhaust fans as in this example, it is preferable that theamount of air to be taken in from the first intake fan 62 is set to belarger than the average of the amounts of air to be discharged from theplurality of exhaust fans 72 a, 72 b, 76 a, 76 b, and 76 c. The reasonfor this is to balance intake air and exhaust air.

Modification Example of the Number of Intake Port

The first side surface 13A of the protruding portion 12B is providedwith only the first intake port 60 as the intake port in the embodiment,but may be further provided with a second intake port 61 as shown inFIG. 17. A porous member 61 a is disposed even in the second intake port61. FIG. 17 shows a schematic plan view of a projector 10 according to amodification example. In the following description, the same elements asthose of the projection device according to the embodiment will bedenoted by the same reference numerals as those of the projection deviceaccording to the embodiment and the detailed description thereof will beomitted.

In the projector 10 shown in FIG. 17, the second intake port 61 isformed on the fourth side surface 13D intersecting the first sidesurface 13A of the protruding portion 12B and a second intake fan 63,which takes in air serving as gas from the second intake port 61 intothe protruding portion 12B, is provided. Further, the projector 10 shownin FIG. 17 comprises a duct 65 that covers the entire surface of thefirst intake fan 62.

With the above-mentioned configuration, almost all air taken into theprotruding portion 12B from the first intake port 60 is guided to thebase portion 12A by the duct 65 and is supplied into the base portion12A. On the other hand, air taken into the protruding portion 12B fromthe second intake port 61 is blown to the light emitting module 30. Apart of the air blown to the light emitting module 30 is discharged tothe outside by the second exhaust fan 76 a, which is provided in theprotruding portion 12B, before flowing into the base portion 12A.Further, the other part of the air is discharged by the second exhaustfans 76 b and 76 c after flowing into the base portion 12A.

Since the second intake port 61 is provided in addition to the firstintake port 60, the first intake port 60 is provided with the firstintake fan 62, and the second intake port 61 is provided with the secondintake fan 63 as described above, the cooling effects of the pluralityof heat sources arranged in the housing to be dispersed can be furtherimproved. That is, in the example shown in FIG. 17, the second intakeport 61 and the second intake fan 63, which are added, can be mainlyused for the cooling of the light emitting module 30 that is one of mainheat sources. For this reason, the cooling effect of each of the heatsources provided in the base portion 12A and the heat source provided inthe protruding portion 12B can be further improved as compared to a casewhere only the first intake port 60 and the first intake fan 62 areprovided.

For example, the LCD 50 for red light, the LCD 52 for green light, andthe LCD 54 for blue light consisting of transmission type LCDs have beenused as electro-optical elements in the above-mentioned example, but theelectro-optical elements are not limited thereto. The transmission typeimage forming panel is not limited to an LCD, and may be, for example, amicro electro mechanical systems (MEMS) shutter panel.

Mechanism for Changing Exhaust Direction

Further, in the projector 10 according to this embodiment, as shown inFIG. 18, the second side surface 13B may be provided with a variablemechanism 130 that changes the exhaust direction of air. The variablemechanism 130 comprises a variable louver 134 that has configuration inwhich a plurality of elongated louver slats 132 are arranged inparallel, and a louver controller 136 (see FIG. 19).

The variable louver 134 is disposed outside the first exhaust port 70.The angle of each louver slat 132 of the variable louver 134 isvariable, and the angle of each louver slat 132 can be changed to changethe discharge direction of air.

The louver controller 136 changes the angle of each louver slat 132 ofthe variable louver 134 in conjunction with the projection direction ofimage light that is projected by the projection lens 11. The projector10 comprises a rotational position detection sensor 111 that detects therotational position of the projection lens 11 about the first opticalaxis A1 and the rotational position of the projection lens 11 about thesecond optical axis A2. The projection direction of image light, whichis projected by the projection lens 11, is determined depending on therotational position about the first optical axis A1 and the rotationalposition about the second optical axis A2. As shown in FIG. 19, thelouver controller 136 is connected to the rotational position detectionsensor 111 that detects the rotational position of the projection lens11 about the first optical axis A1 and the rotational position of theprojection lens 11 about the second optical axis A2. The louvercontroller 136 controls the angle of each louver slat 132 of the louver134 on the basis of information about the rotational positions outputfrom the rotational position detection sensor 111, that is, informationabout the projection direction of image light. For example, the louvercontroller 136 may be adapted to include a look-up table in which theprojection direction of image light is associated with the angle of eachlouver slat and to adjust the angle of each louver slat to a louver slatangle corresponding to the detected projection direction.

With the above-mentioned configuration, the exhaust direction of airdischarged from the first exhaust port 70 can be changed in conjunctionwith the projection direction of image light that is projected by theprojection lens 11.

It is preferable that the louver controller 136 changes the angle ofeach louver slat 132 so that the projection direction of image lightprojected by the projection lens 11 and the exhaust direction of airdischarged from the second side surface 13B are different from eachother. For example, in a case where the projection direction of imagelight projected by the projection lens 11 (the orientation of the thirdoptical axis A3 shown by a broken line in FIG. 20) is the same as theorientation of the second side surface 13B as shown in FIG. 20, thelouver controller 136 tilts the louver slats 132 of the variable louver134 so that the exhaust direction is tilted downward with respect to thesecond side surface 13B. Further, for example, in a case where theprojection direction of image light projected by the projection lens 11(the orientation of the third optical axis A3 shown by a broken line inFIG. 21) is the same as the orientation of the sixth side surface 13F asshown in FIG. 21, the louver controller 136 tilts the louver slats 132of the variable louver 134 so that the exhaust direction of airdischarged from the second side surface 13B is opposite to theprojection direction.

In a case where the angle of each louver slat 132 is changed asdescribed above so that the projection direction of image lightprojected by the projection lens 11 and the exhaust direction of airdischarged from the second side surface 13B are different from eachother, the entry of hot air discharged from the exhaust port into theprojection range of image light projected from the projection lens 11can be suppressed. In a case where the entry of hot air into theprojection range is suppressed, the fluctuation of an image caused bythe hot air can be suppressed. Since it is possible to prevent theintrusion of dust and dirt from the exhaust port by keeping the louverin a closed state as shown in FIG. 18 in a case where the projector 10is not in use, this is preferable.

In the above-mentioned example, the louver controller 136 has beenprovided and the angle of each louver slat has been automaticallyadjusted according to the projection direction of image light. However,the louver controller 136 may not be provided and the orientation ofeach louver slat may be manually changed.

Further, a louver is not limited to the variable louver 134, and alouver of which the angle of each louver slat is fixed may be provided.For example, a louver of which louver slats are mounted at an anglewhere a discharge direction is different from a projection direction tobe frequently used may be provided.

Only the second side surface 13B has been provided with the variablelouver 134 in the above-mentioned example, but only the third sidesurface 13C or both the second side surface 13B and the third sidesurface 13C may be provided with louvers. That is, in a case where thebody part 12 includes the second side surface 13B that is provided onthe base portion 12A and has the same orientation as the first sidesurface 13A or the third side surface 13C that is provided on the baseportion 12A and has an orientation opposite to the orientation of thefirst side surface 13A, the projector 10 may comprise a variablemechanism that changes the exhaust direction of air discharged from theexhaust port (here, the first exhaust port or the second exhaust port)formed on the second side surface or the third side surface inconjunction with the projection direction of the projection lens.Further, the louver may not be provided and the number of rotations ofan exhaust fan provided in an exhaust port provided on a surface havingthe same orientation as the projection direction of the projection lensmay be reduced so that the amount of air to be discharged from theexhaust port is reduced. The louver controller 136 is formed in thecontrol board 22 shown in FIG. 5 and the like, and is controlled by acontrol circuit.

Others

An example in which the projector comprises the intake/exhaust mechanismserving as an air cooling mechanism for cooling heat sources with air asa cooling mechanism for heat sources has been described in eachembodiment, but the projector may further comprise a liquid coolingmechanism for cooling heat sources with liquid. For example, a liquidcooling mechanism 160 can be disposed at a position partiallyoverlapping with the control board 22 in a plan view as shown in FIG.22. Since the projector comprises the liquid cooling mechanism, thecooling effect of each of the heat sources provided in the housing canbe further improved. Examples of the structure of the liquid coolingmechanism are disclosed in, for example, JP2019-78913A orJP2013-164595A.

An example in which the light emitting module 30 included in the lightsource section 23 comprises the semiconductor lasers as thesemiconductor light-emitting elements has been described in eachembodiment, but the light emitting module 30 may include light emittingdiodes as the semiconductor light-emitting elements. Further, an examplein which the projector 10 comprises a yellow phosphor in the lightcombination section 31 of the light source section 23 has been describedin the above-mentioned example, but the projector 10 may use a greenphosphor and a red phosphor instead of the yellow phosphor. Furthermore,a green laser light source and a red laser light source may be usedinstead of the yellow phosphor. Alternatively, the light source section23 is not limited to configuration that includes the light emittingmodule 30 and the light combination section 31, and may comprise ahigh-brightness lamp, such as a xenon lamp, a metal halide lamp, or asuper high-pressure mercury lamp.

All documents, patent applications, and technical standards disclosed inthis specification are incorporated in this specification by referenceso that the incorporation of each of the documents, the patentapplications, and the technical standards by reference is specific andis as detailed as that in a case where the documents, the patentapplications, and the technical standards are described individually.

What is claimed is:
 1. A projection device, comprising: a housing thatincludes a base portion and a protruding portion protruding from thebase portion; a projection lens that projects image light onto aprojection target, is disposed to face the protruding portion, and ismounted on the base portion; a prism that is disposed in the baseportion to face an incident-side end part of the projection lens; aplurality of transmission type electro-optical elements that arearranged to face a plurality of side surfaces of the prism,respectively; and a semiconductor light source that is disposed in theprotruding portion and generates the image light.
 2. The projectiondevice according to claim 1, wherein the semiconductor light source is asemiconductor laser.
 3. The projection device according to claim 1,further comprising a wavelength conversion element that is provided inthe base portion and converts a wavelength of light emitted from thesemiconductor light source.
 4. The projection device according to claim3, wherein the wavelength conversion element is disposed to be close toa side surface, which is closer to the protruding portion, of two sidesurfaces of the base portion facing each other.
 5. The projection deviceaccording to claim 1, wherein: a control board is disposed in the baseportion, and the control board is disposed to be close to a sidesurface, which is farther from the protruding portion, of two sidesurfaces of the base portion facing each other.
 6. The projection deviceaccording to claim 1, wherein each of the plurality of transmission typeelectro-optical elements is a liquid crystal display device.
 7. Theprojection device according to claim 1, wherein two transmission typeelectro-optical elements among the plurality of transmission typeelectro-optical elements are arranged to face each other with the prisminterposed therebetween.
 8. The projection device according to claim 1,further comprising: a first intake fan that takes gas into theprotruding portion from a first intake port formed on one surface of theprotruding portion; and a guide mechanism that guides the gas, which istaken into the protruding portion by the first intake fan, into the baseportion.
 9. The projection device according to claim 8, wherein thefirst intake port is formed on a first side surface of the protrudingportion facing the projection lens.
 10. The projection device accordingto claim 9, wherein: the housing includes a second side surface and athird side surface provided on the base portion, the second side surfacehas a same orientation as the first side surface, and the third sidesurface has an orientation opposite to an orientation of the first sidesurface, and the projection device further comprises a plurality ofexhaust fans that discharge gas from a first exhaust port and a secondexhaust port formed on the second side surface and the third sidesurface, respectively.
 11. The projection device according to claim 9,further comprising a plurality of exhaust fans, wherein, among theplurality of exhaust fans, a number of rotations of at least one of theexhaust fans, which are far from the first intake fan, per unit time islarger than a number of rotations of at least one of the exhaust fans,which are close to the first intake fan, per unit time.
 12. Theprojection device according to claim 10, wherein an amount of gas to betaken in from the first intake fan is larger than an average of amountof gas to be discharged from the plurality of exhaust fans.
 13. Theprojection device according to claim 9, wherein: the housing includes asecond side surface or a third side surface provided on the baseportion, the second side surface has a same orientation as the firstside surface, and the third side surface has an orientation opposite toan orientation of the first side surface, the projection lens includes amechanism for changing a projection direction of the image light, andthe projection device further comprises a variable mechanism thatchanges an exhaust direction of gas discharged from an exhaust portformed on the second side surface or the third side surface inconjunction with the projection direction.
 14. The projection deviceaccording to claim 9, further comprising a second intake fan that takesgas into the protruding portion from a second intake port formed on afourth side surface intersecting the first side surface of theprotruding portion.
 15. The projection device according to claim 2,wherein: a control board is disposed in the base portion, and thecontrol board is disposed to be close to a side surface, which isfarther from the protruding portion, of two side surfaces of the baseportion facing each other.
 16. The projection device according to claim3, wherein: a control board is disposed in the base portion, and thecontrol board is disposed to be close to a side surface, which isfarther from the protruding portion, of two side surfaces of the baseportion facing each other.
 17. The projection device according to claim4, wherein: a control board is disposed in the base portion, and thecontrol board is disposed to be close to a side surface, which isfarther from the protruding portion, of two side surfaces of the baseportion facing each other.
 18. The projection device according to claim2, wherein two transmission type electro-optical elements among theplurality of transmission type electro-optical elements are arranged toface each other with the prism interposed therebetween.
 19. Theprojection device according to claim 3, wherein two transmission typeelectro-optical elements among the plurality of transmission typeelectro-optical elements are arranged to face each other with the prisminterposed therebetween.
 20. The projection device according to claim 4,wherein two transmission type electro-optical elements among theplurality of transmission type electro-optical elements are arranged toface each other with the prism interposed therebetween.